New Jersey, though one of the smaller states, has a varied topography.
In the Northwestern part a section comprising about one-fifth of the area of the state is known as the Highlands and Kitatinny Valley. This region is traversed by several low mountain ridges extending northeasterly across the state with valleys and rolling hills between. The highest of these ranges is the Kittatinny, which rises from the banks of the Delaware River at the famous Delaware Water Gap. To the east the region is studded with numerous lakes, some of the largest being Lakes Hopatcong, Mohawk and Greenwood. Elevations up to 1,800 feet above sea level are found in the Kittatinny Mountains near the New York State line.
South and East of the Highlands is a region of about equal area known as the Red Sandstone Plain, or the Piedmont of New Jersey. It is generally hilly in its northwestern part, becoming rolling and then flat toward the south and southeast. At its northern corner are the Palisades, cliffs which rise abruptly from the Hudson River to heights of 200 to 500 feet. The seacoast section extends from Sandy Hook to Cape May, a distance of about 125 miles. This area is characterized by long stretches of sandy beaches, occupied largely by summer resorts. Tidewater marshes become numerous toward the south.
In the Southern interior a region known as the Pine Barrens is covered with scrubby forest of pine and some oak. The land is low and partly swampy. Here are found the large cranberry bogs of New Jersey. In fact, most of the state that lies south of a line connecting Jersey City and Trenton is low and flat with few elevations higher than 100 feet, these being mainly in Monmouth County.
About 30 percent of the area of New Jersey drains into the Delaware River and Delaware Bay, which forms the western boundary. Nearly half of Sussex County, in the northwest, drains northward through the Wallkill River into the Hudson River. The remainder of the state drains directly into the Atlantic Ocean through the Passaic, Hackensack and Raritan Rivers in the north, and a number of small rivers and streams in the south.
Over the Southern interior the soil changes from sandy near the coast to clay and marl in the western part. However, there is no steady transition, the soil change being affected mostly by alternating stretches of the different soils and combinations of them.
In the most productive sections in the southwestern part, light-to-medium sandy loams predominate. Immense quantities of garden truck for commercial canning, especially tomatoes, are grown in Cumberland, Salem, Gloucester, Camden and western Burlington Counties.
The extreme length of the state is 166 miles and its greatest width only about 65 miles. The difference in climate is quite marked between the southern tip at Cape May and the northern extremity in the Kittatinny Mountains.
The former locality is almost surrounded by water and is fairly well removed from the influence of the frequent storms that cross the Great Lakes region and move out the St. Lawrence Valley. The northern extremity is well within the zone of influence of these storms and, in addition, lies at elevations rising from 800 to 1,800 feet. The influence of these high elevations on the temperature is considerable. The differences between these two localities are particularly marked in winter, Cape May having a normal January temperature about the same as that of southwestern Virginia, while that of Layton, in the extreme northwest, is similar to that of northern Ohio. Since the prevailing winds are mostly offshore, the ocean influence does not have full effect.